Anti-seismic CFRP reinforced concrete column and construction method thereof

Abstract

The invention discloses an anti-seismic CFRP rib concrete column and a construction method thereof. According to the scheme, the anti-seismic CFRP rib concrete column is composed of concrete, an anti-shear sleeve, an anchoring sleeve, a plurality of CFRP sheet stirrups and a plurality of CFRP woven longitudinal ribs in a matched mode. Wherein the plurality of CFRP sheet-shaped stirrups form a plurality of CFRP sheet-shaped stirrup layers, and the CFRP sheet-shaped stirrups are sequentially distributed at intervals in the extending direction of the concrete column; the two ends of a plurality of CFRP woven longitudinal bars are anchored to the anchoring sleeves respectively, the CFRP woven longitudinal bars are arranged in the CFRP sheet stirrup layers respectively, and each CFRP woven longitudinal bar is fixedly connected with the corresponding CFRP sheet stirrup to form a CFRP rib framework. A shear-resistant sleeve is arranged at the part, corresponding to the plastic hinge area of the concrete column and in contact with the CFRP sheet stirrup, of each CFRP woven longitudinal bar; and the concrete is poured on the CFRP rib framework to form a concrete column. The CFRP reinforced concrete column formed by the scheme is excellent in anti-seismic property, and the problem that an existing CFRP reinforced concrete column is poor in compression resistance and anti-seismic property can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the field of civil engineering and construction, and relates to the technical field of concrete column structures, and in particular to a CFRP reinforced concrete column with excellent seismic performance and a construction method thereof. Background Art

[0002] In the field of civil engineering, replacing easily corroded steel bars with corrosion-resistant materials (such as CFRP bars) is an effective way to improve the corrosion resistance of concrete structures. Carbon fiber-reinforced polymer (CFRP) bars have the characteristics of light weight, high strength, and corrosion resistance, and are generally considered to be an ideal substitute for steel bars in corrosive environments.

[0003] CFRP reinforced concrete structures use CFRP bars instead of steel bars in concrete and are currently widely used in the field of civil engineering. However, since CFRP bars are brittle materials, the failure mode of CFRP reinforced concrete structures is brittle failure, which is different from the ductile failure of traditional reinforced concrete structures. In addition, the compressive and shear strengths of CFRP bars are low, and the forces on CFRP bars in CFRP reinforced concrete structures are complex, which often results in the CFRP bars being unable to exert their high tensile strength performance, and the CFRP bars being sheared or compressed in advance, which limits the promotion and application of CFRP reinforced concrete structures.

[0004] At present, some FRP reinforced concrete structure specifications do not recommend using FRP bars as compressive reinforcement materials because of their low compressive strength. However, CFRP bars in CFRP reinforced concrete columns are prone to shear brittle failure under seismic loads. The traditional stirrup form is spiral rod stirrups, which have a weak restraining effect on concrete, and the rod stirrups have a greater shear effect on the longitudinal reinforcement under seismic loads. The compressive strength of CFRP longitudinal bars is low, which leads to low utilization of the tensile strength of CFRP bars.

[0005] It can be seen that how to effectively solve the brittle failure of FRP tendons and improve the strength utilization of CFRP tendons is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0006] In view of the problem that the CFRP bars in existing CFRP reinforced concrete columns are prone to shear brittle failure under seismic loads, the purpose of the present invention is to provide a CFRP reinforced concrete column with excellent seismic performance, and also to provide a preparation method of the CFRP reinforced concrete column, thereby overcoming the problems existing in the prior art.

[0007] In order to achieve the above-mentioned object, the present invention provides a seismic CFRP reinforced concrete column, wherein the CFRP reinforced concrete column comprises concrete, a shear sleeve, an anchor sleeve, and further comprises a plurality of CFRP sheet stirrups and a plurality of CFRP braided longitudinal bars;

[0008] A plurality of CFRP sheet stirrups form a plurality of CFRP sheet stirrup layers and are sequentially spaced and distributed along the extension direction of the concrete column; two ends of a plurality of CFRP braided longitudinal bars are respectively anchored to anchor sleeves, a plurality of CFRP braided longitudinal bars are respectively placed inside each layer of CFRP sheet stirrup layers, and each CFRP braided longitudinal bar is respectively connected to the CFRP sheet stirrups in each layer of CFRP sheet stirrup layers by fixed connection to form a CFRP bar skeleton; a shear sleeve is arranged on each CFRP braided longitudinal bar at a position corresponding to the plastic hinge area of ​​the concrete column and in contact with the CFRP sheet stirrups; the concrete is poured on the CFRP bar skeleton to form a concrete column.

[0009] In some embodiments of the present invention, the CFRP sheet stirrups are formed by winding and stacking multiple layers of carbon fiber composite material filaments and bonding and curing with epoxy resin to form closed stirrups.

[0010] In some embodiments of the present invention, the CFRP sheet stirrups include CFRP outer sheet stirrups and CFRP inner sheet stirrups, and the CFRP inner sheet stirrups can be placed inside the CFRP outer sheet stirrups, and the two can be fixed.

[0011] In some embodiments of the present invention, each layer of CFRP sheet stirrups is composed of one CFRP outer sheet stirrup and two CFRP inner sheet stirrups, the two CFRP inner sheet stirrups are placed perpendicularly to each other inside the CFRP outer sheet stirrups, and the CFRP inner sheet stirrups are fixed to the CFRP outer sheet stirrups.

[0012] In some embodiments of the present invention, each layer of CFRP sheet stirrups is composed of one CFRP outer sheet stirrup and two CFRP inner sheet stirrups, and the two CFRP inner sheet stirrups are respectively placed on the upper side and the lower side of the CFRP outer sheet stirrups and fixed therebetween.

[0013] In some embodiments of the present invention, the CFRP braided longitudinal reinforcement is composed of a CFRP braided longitudinal reinforcement outer layer and a CFRP longitudinal reinforcement axial inner layer, the CFRP braided longitudinal reinforcement outer layer is wrapped around the CFRP longitudinal reinforcement axial inner layer with pre-tension, and the two layers are also bonded by epoxy resin.

[0014] In some embodiments of the present invention, the outer layer of the CFRP braided longitudinal reinforcement is formed by bidirectional spiral braiding of carbon fibers or glass fibers.

[0015] In some embodiments of the present invention, a ribbed structure is formed on the surface of the CFRP braided longitudinal reinforcement.

[0016] In some embodiments of the present invention, the shear sleeve is connected to the CFRP braided longitudinal reinforcement using a crimping structure.

[0017] In order to achieve the above object, the present invention provides a method for preparing a seismic CFRP reinforced concrete column, the preparation method comprising:

[0018] Step 1: Mark the position of the shear sleeve on the CFRP braided longitudinal reinforcement and connect the shear sleeve to the CFRP braided longitudinal reinforcement;

[0019] Step 2: assemble the CFRP sheet stirrups into a CFRP sheet stirrup layer by tying wires;

[0020] Step 3: Anchoring the end of the CFRP braided longitudinal reinforcement formed in step (1) with the anchor sleeve;

[0021] Step 4: placing the CFRP braided longitudinal reinforcement anchored in step (3) inside the CFRP sheet stirrup layer formed in step (2), and forming a CFRP reinforcement skeleton with the CFRP sheet stirrup layer by tying wires;

[0022] Step 5: Place the CFRP reinforcement frame formed in step (4) in a concrete formwork, pour concrete, and obtain a CFRP reinforcement concrete column after curing.

[0023] In some embodiments of the present invention, the preparation method also includes a CFRP braided longitudinal reinforcement preparation step, in which an axial carbon fiber rod is formed by a pultrusion process, and at the same time, an outer layer of the axial carbon fiber rod is braided and wrapped with a certain pre-tension to form an outer layer of the CFRP braided longitudinal reinforcement, and then the outer layer of the CFRP braided longitudinal reinforcement and the axial carbon fiber rod are bonded by epoxy resin.

[0024] Compared with the prior art, the CFRP reinforced concrete column solution with excellent seismic performance of the present invention has the following beneficial effects:

[0025] 1. The CFRP reinforced concrete column with excellent seismic performance improves its seismic performance by adopting a new type of CFRP reinforcement and shear structural measures, solving the problem of poor ductility and poor seismic performance of the CFRP reinforced concrete column.

[0026] 2. This CFRP reinforced concrete column with excellent seismic performance provides an innovative CFRP sheet stirrup structure, which has a strong restraining effect on concrete and a large contact area with the longitudinal reinforcement, thereby weakening the shearing effect of the stirrup on the longitudinal reinforcement under seismic loads.

[0027] 3. The longitudinal reinforcement in the CFRP reinforced concrete column with excellent seismic performance adopts CFRP braided reinforcement, which includes a carbon fiber axial layer and a glass fiber braided layer. The glass fiber braided layer has a restraining effect on the carbon fiber axial layer, has good compressive performance, and improves the tensile strength utilization rate of the CFRP reinforcement.

[0028] 4. In this CFRP reinforced concrete column with excellent seismic performance, a shear sleeve is arranged in the plastic hinge area to weaken the shear effect of the stirrups on the longitudinal reinforcement under the action of seismic load and avoid shear failure of the longitudinal reinforcement. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0030] Figure 1 It is a schematic diagram of the structure of the earthquake-resistant CFRP reinforced concrete column in the present invention.

[0031] Figure 2 This is a schematic diagram of CFRP sheet stirrups in the earthquake-resistant CFRP reinforced concrete column provided by the present invention.

[0032] Figure 3 This is a schematic diagram of the second type of CFRP sheet stirrups in the earthquake-resistant CFRP reinforced concrete column provided by the present invention.

[0033] Figure 4 Schematic diagram of CFRP braided longitudinal reinforcement in the earthquake-resistant CFRP reinforced concrete column provided by the present invention.

[0034] Figure 5 Schematic diagram of the shear sleeve in the earthquake-resistant CFRP reinforced concrete column provided by the present invention.

[0035] Figure 6 This is a schematic cross-sectional view of a CFRP reinforced concrete column in Example 2 of the present invention.

[0036] Figure 7 It is a comparison diagram of the hysteresis curves of Example 1 of the present invention and the traditional CFRP reinforced concrete column.

[0037] The meaning of the reference numerals in the figure are: 1-concrete; 2-1-CFRP sheet outer stirrups; 2-2-CFRP sheet inner stirrups; 3-CFRP braided longitudinal reinforcement; 3-1CFRP longitudinal reinforcement braided layer; 3-2-CFRP longitudinal reinforcement axial layer; 4-shear sleeve; 5-anchor sleeve. DETAILED DESCRIPTION

[0038] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below with reference to specific diagrams.

[0039] In view of the fact that traditional stirrups adopt a rod-shaped cross-section, the contact area between the stirrups and the longitudinal reinforcement in the CFRP reinforcement skeleton is small, the stirrups exert shear force on the longitudinal reinforcement under the action of seismic loads, and the longitudinal reinforcement is prone to shear failure, the present invention constructs innovative CFRP sheet stirrups and CFRP braided longitudinal reinforcement, and then organically cooperates the CFRP sheet stirrups and the CFRP braided longitudinal reinforcement to form a CFRP reinforced concrete column with excellent seismic performance.

[0040] In this CFRP reinforced concrete column, innovative CFRP sheet stirrups are organically matched with CFRP braided longitudinal reinforcements to greatly increase the contact area, which can reduce the shear stress of the stirrups on the longitudinal reinforcement under seismic loads and delay the shear failure of the longitudinal reinforcement. In addition, the CFRP sheet stirrups have a strong restraining effect on the concrete.

[0041] Furthermore, CFRP braided longitudinal reinforcement uses CFRP braided reinforcement, which has better compressive performance.

[0042] Furthermore, by configuring a shear sleeve in the plastic hinge area, the shear effect of the stirrups on the longitudinal reinforcement under the action of seismic loads is weakened.

[0043] The CFRP reinforced concrete column adopts the above-mentioned material form and structural measures, thereby effectively improving the seismic performance.

[0044] Specifically, the CFRP sheet stirrups in the CFRP reinforced concrete column are Figure 2 CFRP sheet stirrups are composed of multiple layers of carbon fiber composite material wires wound and stacked, and then bonded and cured with epoxy resin.

[0045] Specifically, the CFRP sheet stirrup is wound in a thick-walled steel mold, and the winding is stopped when the thickness of the multi-layer fiber composite material wire reaches the thickness of the sheet stirrup, and the closed stirrup is formed by epoxy resin bonding and curing. The bending section strength of the closed sheet stirrup is higher than that of the traditional CFRP rod stirrup, and the material strength utilization rate is high.

[0046] The CFRP braided longitudinal reinforcement in the CFRP reinforced concrete column is composed of an outer layer of CFRP braided longitudinal reinforcement and an axial inner layer of CFRP longitudinal reinforcement. The outer layer of CFRP braided longitudinal reinforcement is wrapped around the axial inner layer of CFRP longitudinal reinforcement with pre-tension and fixed to the axial inner layer of CFRP longitudinal reinforcement. The outer layer of CFRP braided longitudinal reinforcement wrapped around and fixed on the outer surface of the axial inner layer of CFRP longitudinal reinforcement in the CFRP braided longitudinal reinforcement thus formed can form a restraining effect on the axial inner layer of CFRP longitudinal reinforcement, so that the formed CFRP braided longitudinal reinforcement has better compressive performance.

[0047] See also Figure 1 , which is a structural example diagram of the earthquake-resistant CFRP reinforced concrete column provided by the present invention.

[0048] Based on the diagram, the earthquake-resistant CFRP reinforced concrete column provided by the present invention mainly comprises concrete 1, a plurality of CFRP sheet stirrups 2, a plurality of CFRP braided longitudinal bars 3, a plurality of shear sleeves 4, a plurality of anchor sleeves 5, and high-strength grouting material.

[0049] The plurality of CFRP sheet stirrups 2 form a plurality of CFRP sheet stirrup layers, and are sequentially spaced and distributed along the extension direction of the concrete column.

[0050] The ends of several CFRP braided longitudinal bars 3 are respectively placed in the anchor sleeves 5, and the two are connected by high-strength grouting material to achieve anchoring. At the same time, several CFRP braided longitudinal bars 3 are respectively placed inside each layer of CFRP sheet stirrups, and are distributed along the circumference of the corresponding CFRP sheet stirrups in each layer of CFRP sheet stirrups. Each CFRP braided longitudinal bar is fixedly connected to the corresponding CFRP sheet stirrups in each layer of CFRP sheet stirrups to form a CFRP reinforcement skeleton.

[0051] Furthermore, a shear sleeve 4 is provided on each CFRP braided longitudinal reinforcement 3 at a location corresponding to the plastic hinge area of ​​the concrete column and in contact with the CFRP sheet stirrup 2, and the shear sleeve 4 is in contact with the corresponding CFRP sheet stirrup 2.

[0052] On this basis, a CFRP reinforcement skeleton formed by concrete 1 is poured to form a concrete column.

[0053] With respect to the earthquake-resistant CFRP reinforced concrete column provided by the present invention, its implementation scheme and technical features are specifically described below.

[0054] The concrete 1 in the CFRP reinforced concrete column is not limited here and can be determined according to actual needs.

[0055] See also Figure 2 The CFRP sheet stirrups 2 in the CFRP reinforced concrete column are composed of multiple layers of carbon fiber composite material wires wound and stacked. During the specific molding, the multi-layer fiber composite material wire bundles are wound in a thick-walled steel mold, and the winding is stopped when the thickness of the multi-layer fiber composite material wire bundle reaches the thickness of the sheet stirrup, and the closed stirrups are formed by epoxy resin bonding and curing. The bending section strength of the closed sheet stirrup is higher than that of the traditional CFRP rod stirrup, and the material strength utilization rate is high.

[0056] As a further explanation, the CFRP sheet stirrup 2 of such a structure can be prepared by a winding molding process based on a mold during specific implementation. That is, on the outer surface of a thick-walled steel mold, the outer contour size of the mold is consistent with the inner surface size of the CFRP sheet stirrup 2, firstly a single layer of high temperature resistant plastic film is coated, then multiple layers of CFRP tows impregnated with resin are wound on the mold to form a CFRP tube, then a layer of high temperature resistant plastic film is coated, and finally the temperature is raised and solidified to form a stirrup with a rectangular closed cross section.

[0057] As a further explanation, the CFRP sheet stirrups 2 are used to construct FRP outer sheet stirrups 2-1 and CFRP inner sheet stirrups 2-2 of different specifications in specific applications, and the CFRP inner sheet stirrups 2-2 can be placed as a whole inside the FRP outer sheet stirrups 2-1 for combined use.

[0058] As an example, when the FRP outer sheet stirrup 2-1 and the CFRP inner sheet stirrup 2-2 are formed, the four corners of the corresponding outer sheet stirrup 2-1 are preferably arcs with a radius of 30mm, and the four corners of the inner sheet stirrup 2-2 are preferably arcs with a radius of 10mm, and the thickness of the stirrup is preferably 3.5mm or 4mm. On this basis, the width of the FRP outer sheet stirrup 2-1 is preferably 14mm or 16mm, and the width of the CFRP inner sheet stirrup 2-2 is preferably half the width of the FRP outer sheet stirrup 2-1, which is 7mm or 8mm, so as to facilitate combination with the FRP outer sheet stirrup 2-1.

[0059] As a further example, when the CFRP sheet stirrup 2 is used, one FRP outer sheet stirrup 2-1 and two CFRP inner sheet stirrups 2-2 are used to form a CFRP sheet stirrup layer.

[0060] Combination Figure 2 As shown, two CFRP inner sheet stirrups 2-2 are placed as a whole inside the FRP outer sheet stirrups 2-1, specifically one is arranged in the X direction and one in the Y direction, that is, the two CFRP inner sheet stirrups 2-2 are stacked vertically with each other and placed as a whole inside the CFRP outer sheet stirrups 2-1. Since the width of the CFRP inner sheet stirrups 2-2 is half the width of the FRP outer sheet stirrups 2-1, the width of the two vertically stacked CFRP inner sheet stirrups 2-2 is exactly the same as the width of the FRP outer sheet stirrups 2-1, so that they are placed as a whole inside the FRP outer sheet stirrups 2-1. On this basis, each CFRP inner sheet stirrup 2-2 is fixedly connected to the CFRP outer sheet stirrup 2-1 by a binding wire, thereby forming a single-layer stirrup, and the single-layer stirrups and the longitudinal reinforcement are bound by the binding wire to form a CFRP reinforcement skeleton.

[0061] As a further explanation, the CFRP sheet stirrups 2 can also adopt a second assembly scheme in specific applications. This assembly scheme also uses an FRP outer sheet stirrup 2-1 and two CFRP inner sheet stirrups 2-2 to form a layer of CFRP sheet stirrups, wherein the two CFRP inner sheet stirrups are respectively placed on the upper and lower sides of the CFRP outer sheet stirrups and fixed between the two.

[0062] Combination Figure 3 As shown, two CFRP inner sheet stirrups 2-2 are placed outside the outer sheet stirrups 2-1, specifically one each in the X direction and the Y direction. The inner sheet stirrups 2-2 in the X direction are placed on the upper side of the outer sheet stirrups 2-1, and the bottom surface of the inner sheet stirrups 2-2 fits with the top surface of the outer sheet stirrups 2-1. The inner sheet stirrups 2-2 in the Y direction are placed on the lower side of the outer sheet stirrups 2-1, and the top surface of the inner sheet stirrups 2-2 fits with the bottom surface of the outer sheet stirrups 2-1. The two are fixedly connected by binding wires to form a single-layer stirrup. The single-layer stirrups and the longitudinal bars are bound by binding wires to form a CFRP reinforcement skeleton.

[0063] See also Figure 4 The CFRP braided longitudinal reinforcement 3 in the CFRP reinforced concrete column is specifically composed of a CFRP braided longitudinal reinforcement outer layer 3-1 and a CFRP longitudinal reinforcement axial inner layer 3-2. The CFRP braided longitudinal reinforcement outer layer 3-1 is wrapped around the CFRP longitudinal reinforcement axial inner layer 3-2 with pre-tension, and the two layers are also bonded by epoxy resin.

[0064] As a further explanation, the axial inner layer 3-2 of the CFRP longitudinal reinforcement here is preferably composed of axial carbon fiber rods.

[0065] Furthermore, the CFRP braided longitudinal reinforcement outer layer 3 - 1 is specifically formed by bidirectional helical braiding of carbon fibers or glass fibers.

[0066] As a further explanation, the bidirectional spiral braided structure of the outer layer 3-1 of the CFRP braided longitudinal reinforcement in the present CFRP braided longitudinal reinforcement 3 is formed by bidirectional spiral cross-braiding at a certain angle, which can constrain the axial layer, thereby improving its compressive performance; at the same time, the outer braided structure and the axial inner layer of the CFRP longitudinal reinforcement are efficiently combined through resin materials. The bonding interface uses high-performance epoxy resin or polyester resin to ensure a tight interface bond between the outer braided fibers and the inner axial fibers, thereby improving the overall stability and mechanical properties of the component under complex load conditions. At the same time, the bidirectional spiral braided structure, when combined with the axial inner layer 3-2 of the CFRP longitudinal reinforcement, can effectively disperse stress concentration, delay the development of fatigue damage, and improve the seismic performance and long-term service capacity of the concrete column.

[0067] Furthermore, a ribbed structure is formed on the surface of the CFRP braided longitudinal reinforcement 3 to increase the bonding strength between the CFRP braided longitudinal reinforcement and the concrete structure. Specifically, the CFRP braided longitudinal reinforcement is composed of an outer layer of CFRP braided longitudinal reinforcement and an axial inner layer of CFRP longitudinal reinforcement, wherein the ribbed structure is formed by a mold pressing process during the winding and molding process of the outer layer of fibers. While the outer layer of fibers is bidirectionally spirally woven, a periodic raised ribbed structure is generated on its surface by setting mold grooves of corresponding shapes. The ribbed structure and the inner layer of axial fibers are integrated and cured by high-performance resin materials to ensure that the raised portion and the inner layer of fibers have good interface bonding strength.

[0068] As an example, the CFRP braided longitudinal reinforcement 3 of such a structure can be prepared by combining the two processes of pultrusion and weaving to form a molding process. Among them, the axial carbon fiber rod is prepared by pultrusion molding to serve as the axial inner layer 3-2 of the CFRP longitudinal reinforcement; on this basis, carbon fiber or glass fiber is formed by bidirectional spiral weaving, and is woven and wound around the axial carbon fiber rod with a certain pre-tension, thereby forming the outer layer 3-1 of the CFRP braided longitudinal reinforcement of the bidirectional spiral weaving structure; on this basis, the outer layer 3-1 of the CFRP braided longitudinal reinforcement is further bonded and fixed to the axial carbon fiber rod as the axial inner layer 3-2 of the CFRP longitudinal reinforcement by epoxy resin, thereby forming the CFRP braided longitudinal reinforcement 3. Here, a 12.4mm CFRP braided reinforcement is taken as an example, the inner part is an axial carbon fiber rod with a diameter of 12mm, and the outer layer is a CFRP bidirectional spiral weaving layer with a thickness of 0.4mm.

[0069] In the CFRP braided longitudinal reinforcement 3 thus formed, the outer layer 3-1 of the outer CFRP braided longitudinal reinforcement can provide constraints for the inner layer axial carbon fiber rods 3-2, thereby improving the compressive performance of the CFRP braided longitudinal reinforcement.

[0070] As a further explanation, when the CFRP braided longitudinal reinforcement 3 thus formed is combined with the CFRP sheet stirrups 2, the CFRP braided longitudinal reinforcement 3 is passed through the corresponding CFRP sheet stirrups 2, and is tightly attached to the inner side of the CFRP sheet stirrups 2, and is fixed to the CFRP sheet stirrups 2 with binding wires, thereby forming a CFRP reinforcement skeleton.

[0071] See also Figure 5 The shear sleeve 4 in the CFRP reinforced concrete column is placed at the contact point between the CFRP braided longitudinal reinforcement 3 and the CFRP sheet stirrup 2 in the plastic hinge area of ​​the column. The shear sleeve 4 is preferably 50 mm in length, and a crimping structure is used to connect it to the CFRP braided longitudinal reinforcement 3 corresponding to the plastic hinge area of ​​the concrete column and the contact point with the CFRP sheet stirrup 2, and the crimping amount is 0.3 mm. This crimping amount can ensure that the shear sleeve 4 and the CFRP braided longitudinal reinforcement 3 are reliably bonded, and will not cause damage to the CFRP braided longitudinal reinforcement 3 when the shear sleeve 4 is crimped.

[0072] The anchor sleeve 5 in the CFRP reinforced concrete column is preferably an anchor sleeve with a length of 200 mm and a thickness of 6 mm, and is formed with an internal thread inside and adapted to the end of the CFRP braided longitudinal reinforcement 3 .

[0073] As a further explanation, when the anchor sleeve 5 is anchored to the end of the CFRP braided longitudinal reinforcement 3, the end of the CFRP braided longitudinal reinforcement 3 is first inserted into the anchor sleeve 5, and then high-strength grouting material is poured into the anchor sleeve 5. After curing for a predetermined time, the anchoring is completed.

[0074] In order to further illustrate the earthquake-resistant CFRP reinforced concrete column construction scheme provided by the present invention, the present invention further provides a corresponding preparation scheme.

[0075] When preparing the seismic CFRP reinforced concrete column, firstly prepare concrete 1, CFRP sheet stirrups 2, CFRP braided longitudinal reinforcement 3, shear sleeves 4, anchor sleeves 5 and high-strength grouting materials.

[0076] Among them, the CFRP sheet stirrups 2 and the CFRP braided longitudinal reinforcement 3 are prepared according to the above-mentioned scheme; and the shear sleeve 4 and the anchor sleeve 5 can be prepared according to the above-mentioned specification requirements.

[0077] After the basic materials are prepared, the preparation of seismic CFRP reinforced concrete columns is completed based on the following steps:

[0078] Step 1: Mark the position of the shear sleeve of the CFRP braided longitudinal reinforcement 3, and connect the shear sleeve 4 to the CFRP braided longitudinal reinforcement 3 using crimping technology with a crimping amount of 0.3 mm.

[0079] Step 2: A single-layer CFRP sheet stirrup layer is formed by taking one FRP outer sheet stirrup 2-1 and two CFRP inner sheet stirrups 2-2 as a group, wherein the two CFRP inner sheet stirrups 2-2 are placed on the inner side of the FRP outer sheet stirrup 2-1 in a vertically stacked state, and the two CFRP inner sheet stirrups 2-2 are fixedly connected to the FRP outer sheet stirrup 2-1 by binding wires, thereby forming a CFRP sheet stirrup layer.

[0080] Step 3: Place the anchor sleeve 5 at the end of the CFRP braided longitudinal reinforcement 3, and pour high-strength grouting material into the anchor sleeve 5 to complete the anchoring.

[0081] Step 4: Place the CFRP braided longitudinal reinforcement 3 anchored in step (3) inside the CFRP sheet stirrup layer prepared in step (2), and fix it to the CFRP sheet stirrup layer by tying wires to form a CFRP reinforcement skeleton.

[0082] Step 5: Place the CFRP reinforcement frame formed in step (4) in a concrete formwork, pour concrete, and obtain a CFRP reinforcement concrete column after curing for 28 days.

[0083] In the seismic CFRP reinforced concrete column thus prepared, the bending section of the CFRP sheet stirrup has high strength, and the CFRP sheet stirrup has a strong restraining effect on the core area concrete, which can improve the compressive bearing capacity of the CFRP reinforced concrete column. Specifically, the fiber stress distribution of the bending section of the CFRP sheet stirrup is uniform, and it is bonded and cured by high-performance resin, which significantly improves the strength of the bending section to more than 80% of the strength of the straight section; at the same time, the width of the sheet stirrup is significantly increased compared with the traditional stirrup, and its restraining force on the core area concrete is enhanced. Even after the concrete protective layer is peeled off, the CFRP sheet stirrup still has a strong restraining effect on the core area concrete.

[0084] At the same time, the CFRP braided longitudinal reinforcement has high compressive strength, which can improve the lateral bearing capacity of the CFRP reinforced concrete column. Specifically, the CFRP braided longitudinal reinforcement in this scheme is woven by multiple layers of carbon fiber in a bidirectional spiral manner. The braided layer has a strong constraint effect on the axial layer, which can improve the compressive strength of the axial layer. The failure mode of the CFRP reinforced concrete column under seismic load is CFRP reinforcement compression and shear failure. The increase in the compressive strength of the CFRP reinforcement enables the CFRP reinforced concrete column to resist greater horizontal seismic forces and improve the lateral bearing capacity of the CFRP reinforced concrete column.

[0085] Furthermore, shear sleeves were placed in the plastic hinge area of ​​the concrete column to prevent the shear effect of the stirrups on the longitudinal reinforcement under the action of seismic loads, thereby solving the problem of poor compressive and seismic performance of CFRP reinforced concrete columns.

[0086] Furthermore, the CFRP sheet stirrups and CFRP braided longitudinal bars in the seismic CFRP reinforced concrete column are simple to manufacture and convenient for industrial production.

[0087] With respect to the earthquake-resistant CFRP reinforced concrete column provided by the present invention, the implementation scheme and corresponding performance thereof are further illustrated by means of specific application examples.

[0088] Example 1

[0089] Combination Figure 1 As shown, the earthquake-resistant CFRP reinforced concrete column given in this example has a size of 400mmx400mm, a height of 3000mm, and a protective layer thickness of 20mm.

[0090] The seismic CFRP reinforced concrete column is internally configured with 12 CFRP braided longitudinal bars with a diameter of 14 mm. The dimensions of the CFRP sheet outer stirrups are wxt=16x 3.5 mm (w is width, t is thickness), and the cross-sectional dimensions are 350x350 mm. The dimensions of the CFRP sheet outer stirrups are wxt=8x 3.5 mm, and the cross-sectional dimensions are 140 mmx350 mm. The single-layer stirrups are composed of 1 outer stirrup and 2 inner stirrups. The inner stirrups are placed on the inner side of the outer stirrups, and one inner stirrup is arranged in the X and Y directions respectively. The outer stirrups and the inner stirrups are combined into a single-layer stirrup by binding wires. The single-layer stirrups are arranged every 75 mm in the column axis direction. The single-layer stirrups and the longitudinal bars are combined into a CFRP reinforcement skeleton by binding wires.

[0091] Furthermore, at the plastic hinge area of ​​the column, 95mm above the bottom of the column, where the stirrups and longitudinal bars are in contact, each longitudinal bar is pre-crimped with a 50mm long shear sleeve. A 200mm long anchor sleeve is used at the bottom of the longitudinal bar, and high-strength grouting material is poured into the sleeve to complete the anchoring.

[0092] On this basis, the concrete formwork was erected, and the concrete was vibrated with a vibrator during pouring. After 28 days of curing, the formwork was removed to complete the 400mmx400mm CFRP reinforced concrete column.

[0093] Example 2

[0094] like Figure 1 and Figure 6 As shown, the earthquake-resistant CFRP reinforced concrete column given in this example has a size of 300mmx300mm, a height of 2000mm, and a protective layer thickness of 20mm.

[0095] The seismic CFRP reinforced concrete column is internally configured with 8 CFRP braided longitudinal bars with a diameter of 12 mm. The size of the CFRP sheet outer stirrup is wxt=14x 3.5 mm (w is width, t is thickness), and the cross-sectional size is 250x250 mm. The size of the CFRP sheet outer stirrup is wxt=7x 3.5 mm, and the cross-sectional size is 20 mmx250 mm. The single-layer stirrup is composed of 1 outer stirrup and 2 inner stirrups. The inner stirrup is placed inside the outer stirrup, and the two inner stirrups are arranged one in the X direction and one in the Y direction. The outer stirrup and the inner stirrup are tied together to form a single-layer stirrup, such as Figure 5 As shown in the figure, a layer of single-layer stirrups is arranged every 100 mm in the column axis direction, and the single-layer stirrups and longitudinal bars are tied together to form a CFRP reinforcement skeleton.

[0096] Furthermore, at the plastic hinge area of ​​the column, 120mm above the bottom of the column, where the stirrups and longitudinal bars are in contact, a 50mm long shear sleeve is pre-pressed on each longitudinal bar. A 200mm long anchor sleeve is used at the bottom of the longitudinal bar, and high-strength grouting material is poured into the sleeve to complete the anchoring.

[0097] On this basis, the concrete formwork was erected, and the concrete was vibrated with a vibrator during pouring. After 28 days of curing, the formwork was removed to complete the 300mmx300mm CFRP reinforced concrete column.

[0098] See also Figure 7 , which shows a comparison diagram of the hysteresis curves of the seismic-resistant CFRP reinforced concrete column formed in Example 1 and the ordinary CFRP reinforced concrete column obtained through a pseudo-static test.

[0099] Among them, the stirrups of ordinary CFRP reinforced concrete columns use spiral rod-shaped CFRP stirrups, and the longitudinal reinforcement uses CFRP ribbed bars. The hysteresis curves of the two columns are obtained through pseudo-static tests.

[0100] based on Figure 7 From the state shown, it can be seen that the initial stiffness of the earthquake-resistant CFRP reinforced concrete column is higher than that of the ordinary CFRP reinforced concrete column, the hysteresis curve of the earthquake-resistant CFRP reinforced concrete column is relatively full, and the energy dissipation capacity is better than that of the ordinary CFRP reinforced concrete column. Therefore, the earthquake-resistant CFRP reinforced concrete column given in this example has good earthquake resistance.

[0101] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A seismic CFRP reinforced concrete column, comprising concrete, a shear sleeve, and an anchor sleeve, characterized in that: It also includes a number of CFRP sheet stirrups and a number of CFRP braided longitudinal bars; A plurality of CFRP sheet stirrups form a plurality of CFRP sheet stirrup layers and are sequentially spaced and distributed along the extension direction of the concrete column; two ends of a plurality of CFRP braided longitudinal bars are respectively anchored to anchor sleeves, a plurality of CFRP braided longitudinal bars are respectively placed inside each layer of CFRP sheet stirrup layers, and each CFRP braided longitudinal bar is respectively connected to the CFRP sheet stirrups in each layer of CFRP sheet stirrup layers by fixed connection to form a CFRP bar skeleton; a shear sleeve is arranged on each CFRP braided longitudinal bar at a position corresponding to the plastic hinge area of ​​the concrete column and in contact with the CFRP sheet stirrups; the concrete is poured on the CFRP bar skeleton to form a concrete column.

2. The earthquake-resistant CFRP reinforced concrete column according to claim 1, characterized in that: The CFRP sheet stirrups are composed of multiple layers of carbon fiber composite material wires wound and stacked, and are bonded and cured by epoxy resin to form closed stirrups.

3. The earthquake-resistant CFRP reinforced concrete column according to claim 1, characterized in that: The CFRP sheet stirrups include CFRP outer sheet stirrups and CFRP inner sheet stirrups. The CFRP inner sheet stirrups can be placed inside the CFRP outer sheet stirrups, and the two can be fixed.

4. The earthquake-resistant CFRP reinforced concrete column according to claim 3, characterized in that: Each layer of CFRP sheet stirrups is composed of one CFRP outer sheet stirrup and two CFRP inner sheet stirrups. The two CFRP inner sheet stirrups are placed perpendicularly to each other inside the CFRP outer sheet stirrups, and the CFRP inner sheet stirrups are fixed to the CFRP outer sheet stirrups.

5. The earthquake-resistant CFRP reinforced concrete column according to claim 3, characterized in that: Each layer of CFRP sheet stirrups is composed of one CFRP outer sheet stirrup and two CFRP inner sheet stirrups. The two CFRP inner sheet stirrups are respectively placed on the upper side and the lower side of the CFRP outer sheet stirrups, and the two are fixed therebetween.

6. The earthquake-resistant CFRP reinforced concrete column according to claim 1, characterized in that: The CFRP braided longitudinal reinforcement is composed of a CFRP braided longitudinal reinforcement outer layer and a CFRP longitudinal reinforcement axial inner layer. The CFRP braided longitudinal reinforcement outer layer is wound around the CFRP longitudinal reinforcement axial inner layer with pre-tension, and the two layers are bonded by epoxy resin.

7. The earthquake-resistant CFRP reinforced concrete column according to claim 6, characterized in that: The outer layer of the CFRP braided longitudinal reinforcement is formed by bidirectional spiral braiding of carbon fibers or glass fibers.

8. The earthquake-resistant CFRP reinforced concrete column according to claim 6, characterized in that: A ribbed structure is formed on the surface of the CFRP braided longitudinal reinforcement.

9. A method for preparing a seismic CFRP reinforced concrete column, characterized in that: The preparation method comprises: Step 1: Mark the position of the shear sleeve on the CFRP braided longitudinal reinforcement and connect the shear sleeve to the CFRP braided longitudinal reinforcement; Step 2: assemble the CFRP sheet stirrups into a CFRP sheet stirrup layer by tying wires; Step 3: Anchoring the end of the CFRP braided longitudinal reinforcement formed in step (1) with the anchor sleeve; Step 4: placing the CFRP braided longitudinal reinforcement anchored in step (3) inside the CFRP sheet stirrup layer formed in step (2), and forming a CFRP reinforcement skeleton with the CFRP sheet stirrup layer by tying wires; Step 5: Place the CFRP reinforcement frame formed in step (4) in a concrete formwork, pour concrete, and obtain a CFRP reinforcement concrete column after curing.

10. The method for preparing a seismic CFRP reinforced concrete column according to claim 9, characterized in that: The preparation method also includes a CFRP braided longitudinal reinforcement preparation step, in which an axial carbon fiber rod is formed by a pultrusion process, and at the same time, an outer layer of the CFRP braided longitudinal reinforcement is formed by braiding and winding the outer layer of the axial carbon fiber rod with a certain pre-tension, and then the outer layer of the CFRP braided longitudinal reinforcement and the axial carbon fiber rod are bonded by epoxy resin.

Images